diff --git a/wp-admin/includes/class-wp-plugins-list-table.php b/wp-admin/includes/class-wp-plugins-list-table.php
index 956840e5a1..9e648498fe 100644
--- a/wp-admin/includes/class-wp-plugins-list-table.php
+++ b/wp-admin/includes/class-wp-plugins-list-table.php
@@ -321,7 +321,7 @@ class WP_Plugins_List_Table extends WP_List_Table {
 			if ( true === ( $dropins[ $plugin_file ][1] ) ) { // Doesn't require a constant
 				$is_active = true;
 				$description = '<p><strong>' . $dropins[ $plugin_file ][0] . '</strong></p>';
-			} elseif ( constant( $dropins[ $plugin_file ][1] ) ) { // Constant is true
+			} elseif ( defined( $dropins[ $plugin_file ][1] ) && constant( $dropins[ $plugin_file ][1] ) ) { // Constant is true
 				$is_active = true;
 				$description = '<p><strong>' . $dropins[ $plugin_file ][0] . '</strong></p>';
 			} else {